Cetirizine Hydrochloride

What is Cetirizine?

Cetirizine hydrochloride is a medicine which blocks the effects of histamine, a substance the body produces as part of an allergic reaction. In addition to hay fever, cetirizine is licensed to treat chronic hives (urticaria), where it helps reduce itching and the appearance of raised, itchy patches on the skin. It's classed as a non-drowsy antihistamine. Cetirizine hydrochloride tablets are taken as a 10 mg dose once a day.

Cetirizine Hydrochloride Tablet Uses

Cetirizine hydrochloride tablets are used to relieve the symptoms of:

• Seasonal allergic rhinitis (hay fever): nasal and eye symptoms such as sneezing, a runny or blocked nose, and itchy, watery eyes
• Perennial allergic rhinitis: the same nasal and eye symptoms, but from allergies that occur all year round rather than seasonally
• Chronic idiopathic urticaria: ongoing hives with no identifiable trigger, where cetirizine helps reduce itching and calm the raised, itchy patches on the skin. 

Antihistamines like cetirizine are also commonly used for other allergic reactions, including conjunctivitis, eczema flare-ups, reactions to insect bites and stings, and some food allergies.

How Do Cetirizine Hay Fever Tablets Work?

When you come into contact with an allergen, such as pollen, your body releases histamine as part of its immune response. Histamine binds to receptors in your nose, eyes, and skin, triggering the sneezing, itching, and swelling behind hay fever symptoms.

Cetirizine works by blocking these histamine receptors, known as H1-receptors, so that histamine can't produce its usual effects. Studies also suggest it reduces the movement of certain immune cells, called eosinophils, into the skin and eyes during an allergic reaction, based on research where people were exposed to an allergen under controlled conditions.

How Long Does Cetirizine Take to Work?

Most people notice an improvement in their symptoms within an hour of taking cetirizine. This aligns with how quickly the medicine reaches its peak level in the blood, which studies show happens within about an hour of taking a dose, though how you respond can vary from person to person. 

How Effective are Cetirizine Antihistamines? 

In two placebo-controlled trials involving over 500 people with seasonal allergic rhinitis, cetirizine reduced total symptom scores significantly more than placebo, including symptoms measured first thing in the morning. Improvements were seen within the first two weeks of treatment.

For chronic hives, a placebo-controlled trial in 188 patients found that cetirizine controlled symptoms as effectively as the antihistamine hydroxyzine, with both outperforming placebo in reducing the number of hives and how itchy they felt, and cetirizine acting faster than hydroxyzine.

How to Take Cetirizine Tablets

Always take Cetirizine hydrochloride tablets exactly as prescribed by your clinician or doctor. Ask them for advice if you’re ever unsure about what to do. Swallow the tablets with a glass of liquid. You can also divide them into 2 equal doses if necessary.

Treatment duration depends on the type, duration, and course of your symptoms. Ask your clinician or doctor if you need more information. 

Cetirizine Dosage Information

The recommended dose of Cetirizine in adults is 10 mg once per day, taken as 1 tablet. Patients with moderate renal impairment are advised to take 5 mg once daily. If you have severe kidney disease, speak to your clinician or doctor, who may adjust the dosage accordingly.

If you feel that the effect of Cetirizine hydrochloride is too weak or too strong, seek medical advice from your doctor or clinician.

What is the Maximum Dose of Cetirizine in 24 Hours?

The maximum licensed dose of cetirizine in 24 hours is 10 mg, taken as one tablet. If you have moderate kidney impairment, this is reduced to 5 mg. You shouldn't take more than your prescribed dose without speaking to your clinician or doctor first.

In some cases of persistent angioedema symptoms, a doctor may prescribe a higher dose, up to four times the standard amount, but this is a specialist decision that a doctor makes and monitors, not something to increase on your own.

If You Forget to Take Cetirizine Hydrochloride 

If you forget to take your daily Cetirizine tablet, take your next dose as normal. Do not try to take a double dose to make up for one you’ve forgotten. 

If You Take Too Many Cetirizine Tablets

If you think you’ve taken more Cetirizine hydrochloride than you should, seek medical attention from your clinician or doctor, so they can decide what measures (if any) should be taken. After an overdose, the following adverse reactions could occur with increased intensity:

• Confusion
• Diarrhoea
• Malaise
• Urinary retention
• Restlessness
• Sleepiness 
• Abnormal heart rate
• Headache 
• Tiredness

If You Stop Taking Cetirizine

If you stop taking Cetirizine, it will rarely cause any adverse effects. However, it is not impossible. Pruritus (intense itching) and/or Urticaria (hives) may return if you stop taking the medication. In this case, speak to your clinician.

Cetirizine Side Effects and Cautions

Like most medicines, cetirizine can cause side effects, though not everyone experiences them. It's also not suitable for everyone, so it's worth knowing when extra care is needed before starting treatment.

Potential Side Effects of Cetirizine Hydrochloride

Possible side effects of cetirizine are grouped here by how often they're likely to occur:

There are further side effects categorised as ‘very rare’ (1 in 10,000), or for which their frequency is unknown. The full list of side effects can be found in the Patient Information Leaflet online. If you encounter any side effects, either listed or not, you can submit a report to the Yellow Card Scheme. This helps to narrow down the frequency of the effects and helps future users of the treatment.

When to Stop Taking Cetirizine

A severe allergic reaction, possibly shown through a swelling of the face or throat, is classed as a serious side effect. If you encounter this, either soon after you take your first dose or later into the treatment, you should stop taking the medication altogether and speak to a doctor right away.

Cetirizine Warnings and Interactions

Cetirizine antihistamines are an effective hay fever treatment, but they may not suit everyone. For example, you should not take the medication if you have a severe kidney disease that requires dialysis or if you are allergic to:

• Cetirizine dihydrochloride 
• Any other ingredient in the medication
• Hydroxyzine 
• Piperazine derivatives

If you are unsure about whether any of the above applies to you, contact your clinician or doctor for advice. 

Precautions Before Taking Cetirizine Tablets

It’s important that you speak to your doctor or clinician before taking Cetirizine hydrochloride if you:

• Have renal insufficiency. Your clinician may recommend a lower dose if necessary
• Have problems passing urine (such as prostate, bladder, or spinal cord issues)
• Have epilepsy
• Are at risk of convulsions 
• Are intolerant to some sugars, as the medication contains lactose monohydrate

You should also seek medical advice if you are scheduled to have allergy testing, as the medication may affect your test results. You may need to stop taking Cetirizine tablets for several days before the test. 

Cetirizine and Other Medicines

Tell your clinician or doctor if you are taking, or might take, any other medications. This includes any over-the-counter treatments or herbal remedies. This helps them advise you on whether Cetirizine hydrochloride is suitable for your circumstances. 

Driving and Using Machinery

There is no evidence to suggest that the use of Cetirizine will impair your ability to drive or use machinery, so long as you take the recommended dose. Keep a close eye on it to ensure you do not exceed the dose, and monitor your own side effects to make an informed decision. If unsure, contact your clinician.

Pregnancy and Breastfeeding Advice 

If you are pregnant or breastfeeding, think you may be pregnant, or are planning for a baby, it’s essential to consult your clinician or doctor for advice before taking Cetirizine.

More detailed information can be found below: 

Can You Use Cetirizine in Pregnancy?

You should likely avoid the use of Cetirizine if you are pregnant. Accidental use of the medication should not result in harmful effects for the unborn baby, but it should still be avoided as much as possible. Speak to your clinician for further clarification.

Can You Use Cetirizine While Breastfeeding?

You should likely not use Cetirizine while breastfeeding. A small amount of Cetirizine Hydrochloride passes into breast milk while using the medication, and this poses a potential risk to breastfed infants. Consult your clinician about whether you should take it while breastfeeding.

How to Buy Cetirizine in the UK

You can buy Cetirizine from trusted pharmacies and chemists across the UK, either in-store or online. It does not require a prescription and can be picked up over the counter, ready to take as soon as you are.

Can You Buy Cetirizine Online?

Yes, you can buy Cetirizine online from reputable pharmacies like Prescription Doctor. If your seasonal allergies are too strong to even leave the house, we offer next-day delivery right to your doorstep, so you won’t have to step one foot outside.

Frequently Asked Questions About Cetirizine